Hello my name is ***** ***** I will assist you. Check under the dash you should have an inline fuse with the harness giving power to the gages. Most probably that is blown. Replace it and you should go.Noel

Mercruiser not sure of size. The boat is the Olympic edition. There is no fuse block under the helm. There is a 25 amp & 10 amp inline by the battery. Will be pulling the gauges out to trace the wiring later.

ok it can be that the purple wire got disconnected. Check for an empty eylet on one of the gauges as the purple is bridging from all the gauges so if you connect it to any purple one you have power. Noel

Hi Noel. Today I was able to go over to the boat and check it out. We validated the following:1. We found the fuse block. We had to take off the back of the seat on the deck...in front of the helm.2. We found one blown fuse....it was a 10 amp fuse that goes to the secondary stereo accessory (there is nothing hooked to it at this time.) We replaced this fuse.3. The disconnected purple wire was going to the horn...and has been reconnected. The horn functions properly.4. We validated that there is 12 volt dc going to all of the gauges.5. The fuel and volt meters are working fine.6. We checked the grounding going to the gauges...and they are grounded to the grounding block above the motor.7. Oil, trim, tach, temp gauges are NOT working.8. We traced the sending wires back thru the main engine wiring harness...and back to the ICM module.7. At this time, we are concerned that a portion of the ICM module is not functioning completely. The engine runs fine...but (4) gauges do not function. We took the boat out on the water Saturday and ran for a good 3 hours...and the (4) gauges did not function the entire time.8. Do you know any way to troubleshoot the ICM function for the gauges?....or the connection block on the ICM?9. Do you know of anything else we should look at??We look forward to your response. Thanks for your assistance.Regards,

To troubleshoot the engine, you need to connect it to a diagnostic tool and like that you can see that the gauges signal are functioning from the ECU. So you are confirming that there is 12 V going to the VSS and the ground? |There is another 12 v to light up the gauges with the navigation lights. Try making a bridge between these two 12 volts and switch on the lights and see if they are working like that.Noel

Hi Noel,Yes, there appears to be 12 v going to the VSS (ICM) and the ground. I measured the voltage to the back of all of the gauges (11.8 v).I made a bridge between the (2) 12-V cables by connecting purple wire +12V of all the gauges to the +12V for the lights. (the cable for the VSS and the cable for the lights). The lights will work with the bridge...the gauges will not.Any suggestions? Please let me know.Thanks for your help.

so if power is coming to the gauges then the only thing left is the signal, and that comes from the ECM. As i explained earlier to check the output of the ECM you would need to connect it to a diagnostic tool. At this stage i don;t think there are many more options. to go through unless all gauges have had an over voltage or short and have been damaged, but i doubt that. Noel